The highly sensitive flow analysis of disaccharides (maltose, lactose, cellobiose and melibiose) was proposed by using a potential buffer solution and an oxidation-reduction potential(ORP) electrode. The analysis was based on the detection of the change in a composition of the buffer solution with the ORP electrode in a redox-reaction of the disaccharide with a hexacyanoferrate(III) ([Fe(CN)6]3−)-hexacyanoferrate(II) ([Fe-(CN)6]4−) potential buffer solution (containing sodium hydroxide). The sample(140 µl) injected into a water stream was merged with the stream of the buffer solution ([Fe(CN)6]3−-[Fc(CN)6]4−; 5 × 10−5–1 × 10−2 mol dm−3) containing sodium hydroxide(0.6 mol dm−3). The reaction was complete for 4.5 min when the sample flows through the reaction tube(0.5 mm i.d., 20 m long) kept at 85°C. The potential change of the ORP electrode was detected as a peak-shaped, and a linear relationship between the peak height and the concentration of disaccharides was observed in the wide range of 1 × 10−6–1.5 × 10−3 mol dm−3. The lower detection limit was 2.5 × 10−7mol dm−3. Sampling rate for determination was about 60 per hour. The relative standard deviation was 1.7–2.9% for analysis of 5 × 10−6 mol dm−3 maltose at sampling rates of 20–60 h−1.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry